Aptose Biosciences Inc. Annual report pursuant to Section 13 and 15(d)

Note 15 - Income Taxes (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	26.50%	26.50%
Foreign Tax Authority [Member] \| Canada Revenue Agency [Member]
Operating Loss Carryforwards, Total	$ 135.2
Foreign Tax Authority [Member] \| Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards, Total	0.7
Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	19.0
Research Tax Credit Carryforward [Member] \| Domestic Tax Authority [Member] \| Internal Revenue Service (IRS) [Member]
Tax Credit Carryforward, Amount	0.9
Investment Tax Credit Carryforward [Member] \| Foreign Tax Authority [Member] \| Canada Revenue Agency [Member]
Tax Credit Carryforward, Amount	$ 3.6